… And it Comes Out Here

Giving Light a Spin

Ordinary, unpolarized light can be thought of as an equal mixture of clockwise- and counterclockwise-rotating, circularly polarized waves. To create pure, circularly polarized light, a filter can absorb one polarization state and let the other pass through. Such filters are not hard to make, but they are inefficient, since half of the initial light is lost. Liquid crystals are known to emit circularly polarized light, and light from certain semiconductors can become polarized when a magnetic field is used [1]. But these systems are rather large and inflexible in their design.

True, but this ignores lasers which emit linearly polarized light, which can be circularly polarized with a quarter-wave retarder. But there are probably advantages to having it all as a monolithic compact system.

(I also wonder what will happen when someone notices that this system uses a swastika shape, which from a technology standpoint is not particularly surprising — you need a chiral shape, and straight lines are generally the easiest to etch (it has to be a pattern supported by the crystal structure of the material). But given the conservapedia invent-a-furor over relativity, who knows what will happen in the blogohedron?)

Take a Load Off

Flat-ish horizontal space always seems to be at a premium in any lab I’ve worked, and it always fills up. Portable area, which isn’t on the floor (less bending and lifting), is even more so — we have several carts that are supposed to be for temporary equipment, but “temporary” is subjective — sometimes the cart sits there for months on end. Since that invariably leaves nothing free, we have this:



No place for people to sit, but the frequency synthesizer and some tools/components can relax. It gets bad enough that there are times when only one lab stool is free, but it turns out not to be a big deal, since only one section of lab bench (where the best soldering station is located) is remotely likely have any free space on it.

It's That Time of Year Again

I just realized that I’ve passed my Third Blogoversary! Google tells me that three is the Leather Anniversary, which sounds pretty kinky.

I’ll take this opportunity to invite regular visitors who are inclined to leave a comment to give a short summary of who you are/what you do. Do did you come for the physics and stay for the silly posts, or was it the other way around?

F*@&ing Bill O'Reilly — How Does He Work?

Bill “God-of-the-Gaps” O’Reilly. Here’s a follow-on to his bewilderment on how tides work. As long as there is one thing that science can’t explain (or he doesn’t understand), all is well with his world. It’s amazing to me that this argument makes sense to him.

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Golden Gate Diamond Anniversary

Buzz Blog has a post up about the physics of the Golden Gate Bridge. They mention the thermal effects, which I had blogged about this past summer. There is also now a demonstration of the vibrational modes, using a 1/500 scale model:

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There’s also a puzzle at the Buzz Blog link

This quite possibly could be the best business card I have ever seen, because it is not just a cleverly designed graphic, it’s a puzzle: although the diameter of this circle on the card is smaller than that of a quarter, there is a way to get the quarter through the hole. It’s an enigma, get it? Can you figure it out?

There is a way of solving it which does not involve immersing the quarter in liquid nitrogen. (or any other thermal solution)

via Zz

Blogging: You're Doing it Wrong! (Episode IV: A New Hope)

A new hope that it’s over, and yes, this is the last installment. (Thoughts from Science Online 2011) (Part I) (Part II) (Part III)

I think the session on using the history of science had a very interesting point (besides looking at history is interesting and that quote-mining to misrepresent your opponent has been going on for a looong time) — that one has to view science in the context of the time, because we always judge information through the optics of what we think is right, and it’s too easy to fall into the trap of thinking that what we know today is absolutely right, when it isn’t — we’ll keep learning more, and finding out some of what we think we know isn’t accurate. It’s easy to scoff at what people thought was true N years ago, but we have the benefit of hindsight. I am reminded of something from James Burke (from The Day the Universe Changed), when someone had made a condescending remark about people thinking the earth was the center of the solar system:

Somebody apparently once went up the the great philosopher Wittgenstein and said “What a lot of morons people back in the Middle Ages must have been to have looked every morning at what’s going on behind me now, the dawn, and to have thought that what they were seeing was the sun going around the Earth, when as every schoolkid knows the Earth goes around the sun and it doesn’t take too many brains to understand that.”

To which Wittgenstein replied, “Yeah, but I wonder what it would have looked like if the Sun had been going around the Earth.”

Point being, of course, is that it would have looked exactly the same.

You see what your knowledge tells you you’re seeing.

What you think the universe is, and how you react to that in everything you do, depends on what you know. And when that knowledge changes, for you, the universe changes. And that is as true for the whole of society as it is for the individual. We all are what we all know today. What we knew yesterday was different, and so were we.

(It’s from the first two minutes of this episode. The whole series is wonderful.)

Put another way, as an example, nobody was likely to come up with relativity as we know it as long as the notion of the ether was ensconced in everyone’s brains. The presence of a medium was the way things were interpreted, up until you couldn’t think about it that way anymore. And there could be something better than relativity out there.

Which leads me to think that perhaps it’s better to view what we know today as being less wrong than what we knew yesterday.


Another bit of insight came from the “It’s all Geek to me” session, where geekdom and snark were discussed. One of the moderators made the observation that geeks (in the world of geeks and non-geeks, i.e. without going into the difference between geeks, nerds, dweebs and dorks, which is shown here) is that geeks place a high value on information. And my observation, as an extension to that, was that geeks aren’t generally offended by being corrected, as opposed to the non-geek world, where pointing out errors is often considered rude. A geek doesn’t take it personally — being in error isn’t a character flaw (an honest mistake is not the same as lying), and in any discussion it’s better to proceed from the truth than from a mistake.

As far as the snark goes, I’ll just say this — I use snark (OMG, stop the internet!). But snark can’t be a substitute for an answer. I say this more in the context of forum discussions than a blog. Scoffing at someone’s ignorance isn’t productive; for any fact or concept, there was a time when each of us didn’t know it, and we all have huge areas of ignorance. So snark — as a first response — kills discussion. It sends inquisitive people away. But for someone who is proudly and willfully ignorant and shows they aren’t interested in honest discussion, I say, “Fire for effect.”


I also heard the science cheerleader talk, and learned about an interesting method of outreach and destroying some misconceptions; having a professional (pro-sports level) cheerleader point out that she has a technical degree shatters some old but tenacious stereotypes. I also heard about Science for Citizens, which allows average Joes and Janes to contribute to science projects (measuring precipitation where you live, taking samples from streams and ponds, and many other activities, which might be an extension of what you do for work or hobby anyway.

She Sells CSACS Down by the Seashore

And they are only about $1500. Chip-scale atomic clock approaches performance of modules

Which applications need a CSAC, with GPS-based clocks so available and prevalent? First, there are applications where the GPS-based timing may not be accurate enough. But there are also many applications where GPS is unavailable, such as underwater exploration, underground drilling, geophysical research, and EMI shielded rooms. There are also in-the-field military situations where GPS and all EM waves are deliberately jammed by patrols, to prevent remote triggering of improvised explosive devices (IEDs), yet there is a need for precise communication-equipment synchronization among combat teams.

Knowing, with some precision, what time it is also helps in acquiring a GPS signal, too. The advantage of a soldier not having to stand out in a field for a minute or so while a GPS receiver acquires a signal and gives coordinates is left as an exercise for the student.

I’ve seen some, up close and personal; they’re pretty cool. In fact, we had a prototype and I took a picture of it with my novelty dime (3″ diameter) to make it look really small.